1. Unit 4 Day 1 – Magnetic Fields Produced by Electric Currents Magnets Magnetic Fields Surrounding Magnets Magnetic Fields Produced by Electric Currents

2. Magnets Certain materials exhibit ferromagnetic properties, ie: they are surrounded by a magnetic field Magnetic materials are: iron, nickel, cobalt, & gadolinium (and their alloys) Magnets consists of two ends called poles, referred to a north and south The magnetic field surrounding a magnet forms a closed loop through the magnet, in the direction from north to south

3. Magnetic Fields Surrounding Magnets A compass is used to determine the direction of a magnetic field. A compass needle always points away from the north magnetic pole

4. Magnetic Field Surrounding the Earth The earth consists of a magnetic field. Note: The earth’s north-magnetic pole is at the south geographic pole

5. Magnetic Field Between Two Magnetic Poles Magnetic fields between two wide poles of a magnet are nearly uniform with only slight fringing at the edges Magnets always consists of two poles Magnetic mono-poles do not exist in nature and have never been observed

6. Magnetic Fields produced by Electric Currents In 1820 Hans Christian Oersted found that a compass placed close to a current carrying conductor will deflect the needle

7. Magnetic Fields produced by Electric Currents An electric current produces a magnetic field around a wire. The direction of the field follows the Right hand Rule #1